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Effect of topically applied stannous chlorofluoride on the dental caries experience in children II. Results two years after initial treatment
E ffe c t o f t o p ic a lly a p p lie d sta n n o u s c h lo r o flu o r id e o n th e d e n t a l c a r ie s e x p e r ie n c e in c h ild r e n I I . R e s u lts t w o y e a r s a fte r in itia l tr e a tm e n t
Charles L. Howell * D.D.S., M .P.H , Indianapolis, and Joseph C. Muhler, f D .D.S., Ph.D., Bloomington, Ind.
In a previous report1 which presented the effect of topically applied stannous chlo rofluoride at the end of a one year period after the initial treatment, it was shown that stannous chlorofluoride was approx imately 85 per cent more effective than sodium fluoride in reducing the dental caries experience in children. One of the more important variables concerning the utility o f topical fluoride therapy is the length o f time the effectiveness is main tained. Thus, it was of interest to deter mine to what extent the effectiveness of stannous chlorofluoride remained after a two year period. PROCEDURE
The experimental procedures for the con duct of this study— which did not contain a control group— have been reported previously.1 T w o years after the initial series o f four treatments, the children were re-examined by the same dentist who performed the initial series of ex aminations (C .L .H .). R ESU LTS
Table 1, and a breakdown of the age and sex of the subjects completing the study is found in Table 2. The data in Table 1 indicate the percentage reduction pro duced by the stannous chlorofluoride when compared to the effectiveness of the sodium fluoride treatments. N o absolute reductions can be presented because of the absence of a control group in this study. These data indicate that the stannous chlorofluoride was 33 per cent more effec tive after two years than was sodium fluoride as evidenced by the D M F tooth index. This difference is highly signifi cant. The best estimate of the effective ness of stannous chlorofluoride is found in the data in the last column o f Table 1 under total D M F surfaces, which indi cate a superiority o f stannous chlorofluo ride over sodium fluoride of 23 per cent; this difference is highly significant. DISCUSSION
These data would seem to justify the statement that stannous chlorofluoride is ^ In d ia n a S tate Board of H e a lth . fD e p a r tm e n t o f c h em is try,
The anticariogenic effectiveness of the topical fluoride treatments is shown in
In d ia n a
U n iv e rs ity .
I. H o w e ll, C . L., and M u h le r, J . C . E ffe c t o f to p ic a lly a p p lie d stannous c h lo ro flu o rid e on d e n ta l caries e x p e rien c e in c h ild re n . Science 120:316 A u g . 20, 1954,
494 • THE J O U R N A L O F THE A M E R IC A N D EN T A L A S S O C IA T IO N
Table 1 • C o m p a ris o n
b e tw e e n t o p ic a lly a p p lie d sta n n o u s c h lo r o flu o r id e a n d s odiu m flu o r id e on the d e n ta l c a rie s re d u c tio n in c h ild re n t w o y e a rs a f te r the in itia l se rie s o f tre a tm e n ts
G ro u p
N o. of S u bjects
A v. DM F te e th
T o ta l DM F surfa ces
357 363
1.22 1.82
2.74 3.58
1.81 0.0003
3 .30 0.003
S ta n n o u s c h lo r o flu o r id e S o d iu m flu o r id e S ta n d a rd e r r o r o f d iffe re n c e P r o b a b ility % re d u c tio n in c a rie s ra te
33
23
more effective than sodium fluoride as judged by caries increments during the two years after topical application of these compounds to the erupted teeth of children. This conclusion is interesting in light of a previous report2 which demon strated the superiority of stannous fluo ride over sodium fluoride when applied topically to children’s teeth. It thus would appear, as evidenced by two separate clin ical tests, that the presence of the stan nous ion confers additional anticariogenic properties on the fluoride compound. A comparison of the two-year data with the results obtained one year after treatment is presented in Table 3. It is clear that caries rates during the second year were quite similar for the two groups, but the absolute difference in increments
T a b le 2
•
Age
and
s ex
o f s u b je c ts
c o m p le tin g
tw o
y e a r s tu d y
NaF
SnCIF y e a rs
6 7 8 9 10 11 12 13 14 15 T o ta l
Boys
24 43 30 34 30 28 9 3
201
G irls
T o ta l
Boys
G irls
T o ta l
1 15 27 27 30 28 24 4
1 39 70 57 64 58 52 13 3
2 22 27 33 28 29 19 12 1 1
2 21 33 28 32 35 28 9 1
4 43 60 61 60 64 47 21 2 1
156
357
174
189
363
that was seen at the end o f the first year did persist. In the clinical examination of these subjects, some lesions were diagnosed as “ questionable” when no satisfactory de cision could be made as to the presence or absence of caries. Subsequently, these questionable lesions were considered sound surfaces for purposes of calculation of the results, and the reported findings are based on the use of this procedure. It was of interest to determine how the results would have been affected if all questionable lesions had been considered carious instead of noncarious. The twoyear results were not altered by recalcu lation on this basis, but the rather pro nounced effect on the one year values is shown in Table 4. This contrast suggests that the examiner should complete the diagnosis at the time of the examination by demanding of himself in every in stance a final decision of “ carious” or “ noncarious” . It appears that the use of a “ questionable” category for certain conditions omits this decision at the only time when it can be made properly, that is, during the clinical examination. A recent publication3 also does not recom mend the use of a special classification for “ questionable” lesions. Slack4 reported a 36 per cent reduction in the incidence of dental caries in chil dren one year after the topical applica tion of a 2 per cent stannous fluoride so lution. This report is of interest in that this effect was produced even though a half-mouth technic was used in applying the fluoride solution. Such a procedure is to be discouraged when solutions contain-
2. H o w e ll, C . L., a n d o thers. E ffe c t o f to p ic a lly a p p lie d stannous flu o rid e on d e n ta l carie s e xp e rie n c e in c h ild r e n . J .A .D .A . 50:14 J a n . 1955. 3. A m e ric a n D e n ta l A s s o c ia tio n . C lin ic a l te s tin g o f d e n ta l carie s p re v e n tiv e s ; re p o r t o f a c o n fe re n c e to d e v e lo p u n ifo rm s ta n d a rd s a n d p ro c ed u re s in c lin ic a l studies, by C o u n c il on D e n ta l T h e ra p e u tic s , C o u n c il on D e n ta l Research, C o u n c il on D e n ta l H e a lt h . C h ic a g o , A m e ric a n D e n ta l A s s o c ia tio n , 1955. 4. S lack, G . L. E ffe c t ^ o f to p ic a l a p p lic a tio n o f stannous flu o r id e solu tion in th e p re v e n tio n o f d e n ta l c arie s. (A b s tO J . D . Res. 34:785 O c t . 1955.
H O W E L L — M U H L E R . . . V O L U M E 55, O C T O B E R 1957 • 495
T a b le 3
•
re s u ltin g
C o m p a r is o n fro m
th e
of
d e n ta l
to p ic a l
c a r ie s
tr e a t m e n t
of
in c re m e n ts s ta n n o u s
T a b le 4
•
C o m p a r is o n
b e tw e e n
th e
d e n ta l
c a rie s
in c re m e n ts o n e y e a r a f t e r t o p ic a l t r e a t m e n t w ith e it h e r
c h lo r o flu o r id e a n d sodium flu o r id e a f t e r o n e a n d tw o
s ta n n o u s c h lo r o f lu o r id e
y e a rs
q u e s tio n a b le
lesions
o r s o d iu m
w e re
flu o r id e
c la s s e d
as
w hen
n o n c a r io u s
th e or
c a rio u s No. G ro u p
of y e a rs
N o . of s u b jec ts
DMF
DMF
te e th
s u rfa c e s
in c re m e n t
in c r e m e n t*
C la s s ific a tio n of
G ro u p
q u e s tio n a b le One
NaF
397
SnC IF
394
% Two
0 .6 2 0 .0 8 87
s u p e r io r ity
1.39
NaF
363
1.82
3 .5 8
357
1.22
2 .7 4
s u p e r io r ity
33
DMF s u rfa c e s
in c re m e n t
in c re m e n t
0 .5 6 60
SnCIF %
lesions
DMF te e th
23
* ln the p a p e r p re s e n tin g th e results a fte r one y ea r, th e surface incre m e n ts w e re a c tu a lly based on newly d e c a y e d , m issing, o r fille d surfaces in pre vious ly carious te e th , r a th e r th a n on p re vio u s ly noncarious te e th , as r e p o r te d . The D M F s u rfa ce d a ta in T a b le 3 a re based on a ll te e th , as a re those in th e o th e r ta b le s in this p a p e r.
N o n c a r io u s
NaF
0 .6 2
1.39
S n C IF
0 .0 8
0 .5 6
% C a r io u s
87
60
NaF
0 .8 2
1.55
S n C IF
0 .3 6
0 .9 0
%
SU M M ARY
ing a stannous salt are used because of the fact that the stannous ion has such a pronounced affinity for the enamel sur face even when present in micro concen trations. Studies performed at Indiana University in which electron micrographs of the enamel surface were made of teeth from untreated tooth quadrants before and after half-mouth applications defi nitely suggest a transfer o f the stannous ion to the untreated tooth. It would seem only reasonable to suggest that in no in stance should such a half-mouth technic be used until it could be proved beyond any reasonable doubt that there was no effect of the treatment solution on the teeth of the untreated quadrants.
s u p e r io r ity
s u p e r io r ity
55
42
*
Tw o years after the initial topical treat ment of children’s teeth, stannous chloro fluoride was significantly more effective than sodium fluoride in reducing dental caries. When the differences were deter mined by the D M F tooth index, the su periority of stannous fluoride was 33 per cent, and by the D M F surface index the superiority was 23 per cent. Both of these differences are highly significant. An effect on caries reduction values (at the end of the first year) was shown wheh the questionable lesions were considered either as noncarious or carious. It is sug gested that a decision as to “ carious” or “ noncarious” must be made regarding every lesion during the time the clinical examination is being performed.
D rudgery • T he everyday cares and duties, which men call drudgery, are the weights and counter poises o f the clock o f time, giving its pendulum a true vibration, and its hands a regular m otion ; and when they cease to hang upon the wheels, the pendulum no longer swings, the hands no longer move, and the clock stands still. H enry W adsworth Longfellow .
Charles L. Howell * D.D.S., M .P.H , Indianapolis, and Joseph C. Muhler, f D .D.S., Ph.D., Bloomington, Ind.
In a previous report1 which presented the effect of topically applied stannous chlo rofluoride at the end of a one year period after the initial treatment, it was shown that stannous chlorofluoride was approx imately 85 per cent more effective than sodium fluoride in reducing the dental caries experience in children. One of the more important variables concerning the utility o f topical fluoride therapy is the length o f time the effectiveness is main tained. Thus, it was of interest to deter mine to what extent the effectiveness of stannous chlorofluoride remained after a two year period. PROCEDURE
The experimental procedures for the con duct of this study— which did not contain a control group— have been reported previously.1 T w o years after the initial series o f four treatments, the children were re-examined by the same dentist who performed the initial series of ex aminations (C .L .H .). R ESU LTS
Table 1, and a breakdown of the age and sex of the subjects completing the study is found in Table 2. The data in Table 1 indicate the percentage reduction pro duced by the stannous chlorofluoride when compared to the effectiveness of the sodium fluoride treatments. N o absolute reductions can be presented because of the absence of a control group in this study. These data indicate that the stannous chlorofluoride was 33 per cent more effec tive after two years than was sodium fluoride as evidenced by the D M F tooth index. This difference is highly signifi cant. The best estimate of the effective ness of stannous chlorofluoride is found in the data in the last column o f Table 1 under total D M F surfaces, which indi cate a superiority o f stannous chlorofluo ride over sodium fluoride of 23 per cent; this difference is highly significant. DISCUSSION
These data would seem to justify the statement that stannous chlorofluoride is ^ In d ia n a S tate Board of H e a lth . fD e p a r tm e n t o f c h em is try,
The anticariogenic effectiveness of the topical fluoride treatments is shown in
In d ia n a
U n iv e rs ity .
I. H o w e ll, C . L., and M u h le r, J . C . E ffe c t o f to p ic a lly a p p lie d stannous c h lo ro flu o rid e on d e n ta l caries e x p e rien c e in c h ild re n . Science 120:316 A u g . 20, 1954,
494 • THE J O U R N A L O F THE A M E R IC A N D EN T A L A S S O C IA T IO N
Table 1 • C o m p a ris o n
b e tw e e n t o p ic a lly a p p lie d sta n n o u s c h lo r o flu o r id e a n d s odiu m flu o r id e on the d e n ta l c a rie s re d u c tio n in c h ild re n t w o y e a rs a f te r the in itia l se rie s o f tre a tm e n ts
G ro u p
N o. of S u bjects
A v. DM F te e th
T o ta l DM F surfa ces
357 363
1.22 1.82
2.74 3.58
1.81 0.0003
3 .30 0.003
S ta n n o u s c h lo r o flu o r id e S o d iu m flu o r id e S ta n d a rd e r r o r o f d iffe re n c e P r o b a b ility % re d u c tio n in c a rie s ra te
33
23
more effective than sodium fluoride as judged by caries increments during the two years after topical application of these compounds to the erupted teeth of children. This conclusion is interesting in light of a previous report2 which demon strated the superiority of stannous fluo ride over sodium fluoride when applied topically to children’s teeth. It thus would appear, as evidenced by two separate clin ical tests, that the presence of the stan nous ion confers additional anticariogenic properties on the fluoride compound. A comparison of the two-year data with the results obtained one year after treatment is presented in Table 3. It is clear that caries rates during the second year were quite similar for the two groups, but the absolute difference in increments
T a b le 2
•
Age
and
s ex
o f s u b je c ts
c o m p le tin g
tw o
y e a r s tu d y
NaF
SnCIF y e a rs
6 7 8 9 10 11 12 13 14 15 T o ta l
Boys
24 43 30 34 30 28 9 3
201
G irls
T o ta l
Boys
G irls
T o ta l
1 15 27 27 30 28 24 4
1 39 70 57 64 58 52 13 3
2 22 27 33 28 29 19 12 1 1
2 21 33 28 32 35 28 9 1
4 43 60 61 60 64 47 21 2 1
156
357
174
189
363
that was seen at the end o f the first year did persist. In the clinical examination of these subjects, some lesions were diagnosed as “ questionable” when no satisfactory de cision could be made as to the presence or absence of caries. Subsequently, these questionable lesions were considered sound surfaces for purposes of calculation of the results, and the reported findings are based on the use of this procedure. It was of interest to determine how the results would have been affected if all questionable lesions had been considered carious instead of noncarious. The twoyear results were not altered by recalcu lation on this basis, but the rather pro nounced effect on the one year values is shown in Table 4. This contrast suggests that the examiner should complete the diagnosis at the time of the examination by demanding of himself in every in stance a final decision of “ carious” or “ noncarious” . It appears that the use of a “ questionable” category for certain conditions omits this decision at the only time when it can be made properly, that is, during the clinical examination. A recent publication3 also does not recom mend the use of a special classification for “ questionable” lesions. Slack4 reported a 36 per cent reduction in the incidence of dental caries in chil dren one year after the topical applica tion of a 2 per cent stannous fluoride so lution. This report is of interest in that this effect was produced even though a half-mouth technic was used in applying the fluoride solution. Such a procedure is to be discouraged when solutions contain-
2. H o w e ll, C . L., a n d o thers. E ffe c t o f to p ic a lly a p p lie d stannous flu o rid e on d e n ta l carie s e xp e rie n c e in c h ild r e n . J .A .D .A . 50:14 J a n . 1955. 3. A m e ric a n D e n ta l A s s o c ia tio n . C lin ic a l te s tin g o f d e n ta l carie s p re v e n tiv e s ; re p o r t o f a c o n fe re n c e to d e v e lo p u n ifo rm s ta n d a rd s a n d p ro c ed u re s in c lin ic a l studies, by C o u n c il on D e n ta l T h e ra p e u tic s , C o u n c il on D e n ta l Research, C o u n c il on D e n ta l H e a lt h . C h ic a g o , A m e ric a n D e n ta l A s s o c ia tio n , 1955. 4. S lack, G . L. E ffe c t ^ o f to p ic a l a p p lic a tio n o f stannous flu o r id e solu tion in th e p re v e n tio n o f d e n ta l c arie s. (A b s tO J . D . Res. 34:785 O c t . 1955.
H O W E L L — M U H L E R . . . V O L U M E 55, O C T O B E R 1957 • 495
T a b le 3
•
re s u ltin g
C o m p a r is o n fro m
th e
of
d e n ta l
to p ic a l
c a r ie s
tr e a t m e n t
of
in c re m e n ts s ta n n o u s
T a b le 4
•
C o m p a r is o n
b e tw e e n
th e
d e n ta l
c a rie s
in c re m e n ts o n e y e a r a f t e r t o p ic a l t r e a t m e n t w ith e it h e r
c h lo r o flu o r id e a n d sodium flu o r id e a f t e r o n e a n d tw o
s ta n n o u s c h lo r o f lu o r id e
y e a rs
q u e s tio n a b le
lesions
o r s o d iu m
w e re
flu o r id e
c la s s e d
as
w hen
n o n c a r io u s
th e or
c a rio u s No. G ro u p
of y e a rs
N o . of s u b jec ts
DMF
DMF
te e th
s u rfa c e s
in c re m e n t
in c r e m e n t*
C la s s ific a tio n of
G ro u p
q u e s tio n a b le One
NaF
397
SnC IF
394
% Two
0 .6 2 0 .0 8 87
s u p e r io r ity
1.39
NaF
363
1.82
3 .5 8
357
1.22
2 .7 4
s u p e r io r ity
33
DMF s u rfa c e s
in c re m e n t
in c re m e n t
0 .5 6 60
SnCIF %
lesions
DMF te e th
23
* ln the p a p e r p re s e n tin g th e results a fte r one y ea r, th e surface incre m e n ts w e re a c tu a lly based on newly d e c a y e d , m issing, o r fille d surfaces in pre vious ly carious te e th , r a th e r th a n on p re vio u s ly noncarious te e th , as r e p o r te d . The D M F s u rfa ce d a ta in T a b le 3 a re based on a ll te e th , as a re those in th e o th e r ta b le s in this p a p e r.
N o n c a r io u s
NaF
0 .6 2
1.39
S n C IF
0 .0 8
0 .5 6
% C a r io u s
87
60
NaF
0 .8 2
1.55
S n C IF
0 .3 6
0 .9 0
%
SU M M ARY
ing a stannous salt are used because of the fact that the stannous ion has such a pronounced affinity for the enamel sur face even when present in micro concen trations. Studies performed at Indiana University in which electron micrographs of the enamel surface were made of teeth from untreated tooth quadrants before and after half-mouth applications defi nitely suggest a transfer o f the stannous ion to the untreated tooth. It would seem only reasonable to suggest that in no in stance should such a half-mouth technic be used until it could be proved beyond any reasonable doubt that there was no effect of the treatment solution on the teeth of the untreated quadrants.
s u p e r io r ity
s u p e r io r ity
55
42
*
Tw o years after the initial topical treat ment of children’s teeth, stannous chloro fluoride was significantly more effective than sodium fluoride in reducing dental caries. When the differences were deter mined by the D M F tooth index, the su periority of stannous fluoride was 33 per cent, and by the D M F surface index the superiority was 23 per cent. Both of these differences are highly significant. An effect on caries reduction values (at the end of the first year) was shown wheh the questionable lesions were considered either as noncarious or carious. It is sug gested that a decision as to “ carious” or “ noncarious” must be made regarding every lesion during the time the clinical examination is being performed.
D rudgery • T he everyday cares and duties, which men call drudgery, are the weights and counter poises o f the clock o f time, giving its pendulum a true vibration, and its hands a regular m otion ; and when they cease to hang upon the wheels, the pendulum no longer swings, the hands no longer move, and the clock stands still. H enry W adsworth Longfellow .